534WATER REPELLENT

New Hampshire Department of Transportation Standard Specifications – 2016 Description

1.1Water repellent shall be applied to the concrete surfaces shown on the plan or as ordered. Surfaces to be treated shall normally

consist of the following portions of all bridges: concrete curbs, sidewalks (top, fascia, bottoms), wingwalls, piers, and abutment face walls and bridge seats when not coated with epoxy coating. Materials

2.1Water repellent (Silane/Siloxane) shall be a product as included on the Qualified Products List.

Construction Requirements

3.1General. All caulking, patch, and joint sealers shall be installed prior to application of the water repellent. Concrete surfaces

shall have cured a minimum of 14 days and shall be dry prior to the application of water repellent. Minimum substrate and ambient application temperatures shall be as noted on the Qualified Products List for the product used except as allowed in 3.1.2 and 3.1.3. Do not apply when substrate surface temperature exceeds 85°. 3.1.1 All surfaces specified for treatment, that require finishing, shall be protected from freezing and de-icing chemicals until coated with water repellent. All finished surfaces specified for treatment must be treated before winter shutdown. 3.1.2 If the project schedule requires that surfaces be coated outside the product application temperatures listed in the Qualified Products List, those surfaces shall be recoated during the next construction season with the same product when the application temperature is within the listed temperature range and other conditions meet manufacturer’s recommendations durin g the next construction season. Prior to reapplication of water repellent, the surface shall be thoroughly cleaned by water blasti ng and allowed to dry. 3.1.3 If cold weather concreting practices as descr ibed in 520.3.7 are being followed, the 14- day provision of 3.1 is waived. The concrete shall be coated as soon as it is dry after the five-day period specified in 520.3.7 and it shall be protected from freezing until coated. Concrete that is treated with water repellent under these conditions shall be recoated as described in 3.1.2.

3.2Water repellant (silane/siloxane) shall be applied at the heaviest coverage recommended by the manufacturer. Ambient

application temperatures, except as allowed in sections 3.1.2 and 3.1.3, shall conform to the product application temperature listed on the Qualified Products List. 3.2.1 A test application shall be performed on the surface to be treated, to ensure compatibility, using the same equipment to be used on the project. After a minimum of three days, the Engineer shall test for waterproof effectiveness by applying water t o the surface. If the water beads up and is not readily absorbed, the test is positive. 3.2.2 The Contractor shall follow the manufacturer’s instructions in the method of preparation of the concrete and application of the sealer. 3.2.3 The Contractor shall protect the concrete surface from rust staining. Any staining that does occur shall be removed by mopping with a solution containing 1lb. of oxalic acid powder per gallon of water. After 2 or 3 hours, rinse the surface with clear water, scrubbing at the same time with a stiff brush. Tough stains may require a second treatment. If rust stains still persist, other means of removal may be allowed by the Engineer. Areas that had been coated with water repellant prior to removal of rust stains shall be recoated at the application rate specified in 3.2. Method of measurement

4.1Water repellent (Silane/Siloxane), applied to surfaces within the limits shown in the plans or specified herein and at the rate

required will be measured by the gallon.

4.2Water repellant used to recoat areas where rust stains were removed will not be measured for payment.

4.3The Engineer’s estimated quantity of Water Repellant (Silane/Siloxane) is based on an application rate of 150 sf/gal.

Basis of Payment

5.1Water repellent will be paid for at the Contract unit price per gallon, complete in place. The reapplication of water repellent

as required in 3.1.2 and 3.1.3 will be done at the Contractor ’s expense unless the required reapplication was due to circumstances beyond the Contractor’s control, as determined by the Engineer.

5.2Removal of rust stains and recoating with water repellant will be at the Contractor’s expense.

5.3The pay quantity of Water Repellant (Silane/Siloxane) shall be the actual amount used as per 534.3.2.

Pay items and units:

534.3Water Repellent (Silane/Siloxane) Gallon

New Hampshire Department of Transportation Standard Specifications – 2016

Description

This work shall consist of furnishing and placing on concrete surfaces as shown on the plans a flexible, minimum two -coat,

epoxy coating system consisting of a mortar coat and one or more seal coats. The resulting color shall be approximately the shade of hardened concrete. Materials

Epoxy coating shall be an epoxy compound and shall be furnished in two components for combining immediately prior to

use in accordance with the stipulations in this specification. The epoxy coating system shall be a product approved by the Engineer. 2.1.1 The material for the mortar coat shall consist of 100 percent solids. The Component “ A” shall be an epoxy resin containing a t hixotropic agent. The Component “ B” (Hardener) shall be chemically pure amido -amine or poly -amide with no other fillers, diluents or wettings, or volatile solvents. Sand shall be used in the mortar coat. The proportion of sand in the epoxy mortar shall be as recommended by the manufacturer. The two components of the epoxy system furnished under this specification shall be supplied in separate pre-proportioned containers. A unit of Component “ A” shall be supplied in a container with enough capacity to allow the mixing in it of the Component “ B”, together with the sand for the mortar coat. 2.1.2 The material for the seal coat shall consist of a pigmented, solvent-cut two-component epoxy polyamide. The color shall be concrete gray. 2.1.3 Containers shall be identified as “ Component A, Contains Epoxy Resin” and “ Component B, Contains Hardener”. Labels shall show the component type, whether trowel grade or brush grade, mixing directions, and usable temperature range, all as defined by this specification. Each container shall be marked with the name of the manufacturer, the lot or batch number, the date of packaging, pigmentation, if any, and the quantity contained therein in pounds and gallons. 2.1.4 At 70 °F, the mortar grade shall have a pot life of at least 45 minutes and the brush grade shall have a pot life of at least 8 hours. 2.1.5 The epoxy shall be formulated for application at a temperature of 40 °F and above. 2.1.6 Storage. The Components A and B should be stored in a cool place in warm weather and a warm place in cold weather.

2.2Sand for mortar coat shall be Ottawa silica sand, or an approved equivalent, which will closely approximate the color of

concrete. The sand shall be so graded that 100 percent by weight will pass a No. 4 sieve, 20 to 30 percent will pass a No. 50 sieve and 0 to 5 percent will pass a No. 100 sieve. 2.2.1 Sand shall be furnished on the project as a pre-dried product in moisture-proof containers. Construction Requirements

Preparation and surfaces. Acid etching will not be allowed. Surfaces of concrete shall not be “ finished” but shall be

sandblast cleaned before applying the first coat, not only to remove all film or laitance, but also to remove the surface of the concrete deep enough to eliminate any formation over voids. The object is to obtain a durable concrete surface. The area to be treated must be surface-dry, and all dust and sand residue from blast cleaning shall be removed. The temperature of the concrete shall be 40 °F or above. Concrete shall be cured a minimum of 14 days, before coating is applied.

Mixing. Mixing of the epoxy shall be done immediately prior to use and strictly in accordance with the manufacturer’s

directions shown on the container. The epoxy resin and hardener shall be mixed the specified time using an approved propeller - type stirrer designed for the quantity to be mixed. For the mortar coat, after the 2 components have been thoroughly mixed, sand shall be added strictly in the proportion ordered, and mixing shall be continued until a homogeneous mixture has been obtained.

3.3Applications.

3.3.1 Mortar coat. The epoxy and sand mixture shall be applied with a screed or trowel to completely fill all cavities or imperfections present in the concrete. Depending upon the particular brand used and the quality of the concrete surface, to cover 30 ft2 of area with the trowel coat may require approximately 1 gal of the mixture. 3.3.2 Seal coat. After the mortar coat has hardened, the seal coat shall be applied as soon as possible using a brush or roller in the manner recommended by the manufacturer and taking extreme care to fill all pinholes or other voids which may exist in the underlying coat. It is estimated that to cover approximately 200 ft2 of surface will require 1 gal of epoxy seal coat. 3.3.3 In case adequate coverage has not been obtained, one or more additional coats may be ordered.

3.4Safety precautions. Proper protective equipment shall be used and other actions shall be taken against the possibility of

skin damage to humans and against the possibility of fire, since the material may be a dermatitis producer and a fire hazard.